Controllers that accommodate an electronic circuit board and the like in a case have been known in various fields. It is suggested that a plurality of heat release fins are provided on an upper surface of the case used for the controller in order to dissipate the heat from a heat-generating component (e.g. power transistor) installed on the electronic circuit board in the case (see, for instance, Patent Literature 1).
A connector housing for attaching a case-side connector (receptacle connector), a relay housing for attaching a relay and a fuse housing for attaching a fuse are provided on the upper surface of the case disclosed in Patent Literature 1 in addition to the heat release fin.